He replaced Reza Mohajeri, who lost the Qazvin-based club last week.
Rahmati had been appointed as Havadar coach in July as Masoud Shojaei’s replacement but the team lost seven out of 13 matches under his leadership.
Rahmati played for Iran’s national football team from 2004 to 2014. He also played for Esteghlal in two stints.
Shams Azar is scheduled to play Esteghlal on Monday.